Motor control switch mechanism



1932- G. H. WHITTINGHAM 1,890,338

MOTOR CONTROL SWITCH MECHANISM Filed April 22. 1931 3 Sheets-Sheet l1932. a. H. WHITTINGHAM 1,390,838

MOTOR CONTROL SWITCH MECHANISM Filed April 22. 1931 s Sheets-Sheet 2Ill/l 3, 1932 e. H. WHITTINGHAM MOTOR CONTROL SWITCH MECHANISM FiledApril 22. 1931 3 Sheets-Sheet 3 I] l I 1', I I l amt;

Patented Dec. 13, 1932 UNITED STATES PATENT OFFICE GFDBGE H.WHITTINGHAM, OF BALTIMORE, MARYLAND; SAFE DEPOSIT AND TRUST COMPANY OFBALTIMORE AND ELEANOR V. D. WHITTINGHAM, EXECUTORS OF SAID GEORGE H.WHITTINGEAM, DECEASED, ASSIGNORS TO MONITOR CONTROLLER COM- PANY, OFBALTIMORE, MARYLAND, A CORPORATION OF MARYLAND MOTOR CONTROL SWITCHMECHANISM Application filed April 22,

This invention relates to improvements in switches for controllingelectric motors. Machine tools in factories j are commonly equipped withindividual driving motors, and, at a oint convenient to the operator ofthe machlne, push button switches are arranged for controlling anelectro-magnetic switch or contactor which operates to start and stopthe motor. It is found desirable to provide manually operable means foropening the motor circuits, to stop the motor, in case of failure of theelectromagnetic switch to open when the stop push button is pressed.Such failure may arise, for instance, through such groundingof themagnet coil as would short-circuit the push button switches and leavethe coil energized. i

In the present invention, I have associated with the electromagneticswitch a block of insulating material carrying the normally stationarycontacts of the switch, and means whereby this block may be quicklymoved, by the operation of a hand lever, to carry these contactsawayfrom the movable arm of the switch, thereby opening the motor circuitand also disconnecting the magnet coil from the supply circuit. In thismovement of the contact-carrying block, the circuit to the motor isbroken at a plurality of points, thereby minim zing the arcing at thecontacts. After the fault in the electromagnetic switch has beenrepaired, the contact-carrying block may be returned to its normalposition by a reverse movement of the hand 'lever.

In the accompanying drawings,

Fig. 1 is a front elevation of a three-pole switch mechanism;

Fig. 2 is a side elevation of the same, lookin from right to left inFig. 1;

ig. 3 is a central vertical section through the switch mechanism;

Fig. 4 is a cross section on the line 44 of Fig. 3;

, Fig. 5 is a diagrammatic view showing the circuits, the swltchmechanism being shown infront elevation, with parts removed;

Fig. 6 is a front elevation of a single pole switch with a blow-outmagnet;

Fig. 7 is a central vertical section through the same; i

1931. Serial No. 532,065.

Fig. 8 is a transverse section on the line 88 of Fig. 7, and,

Fig. 9 is a detail view of one of the pole pieces of the blow-outmagnet.

Referring to Figs. 1 to 5 inclusive of the drawing, a indicates asuitable base, of insulating material, upon which is mounted anelectromagnet b to which is hingedly connected an armature 1. A strip ofinsulating material 2 is secured to the armature, and con tact fingers3, 4, and 5 are yieldingly mounted upon the strip. These contact fingerscarry metal parts 3*, 4, and 5 at their free ends, each adapted toengage a pair of normally stationary contacts, when the armatureis'attracted by the magnet.

These pairs of contacts, 6-7, 89, 10-11, which may be termed main switchcontacts, and other contacts 12, 13, and 14, which may be termed linecontacts, are mounted on a. block of insulating material 0 which isarranged between and secured to two metal bars, 15 and 16, the lowerends of which are hinged to posts 17 and 18, respectively, and theseposts are secured to the base a. The bars 15 and 16 and the block withits contacts are normally supported in the position shownin full linesin Fig. 3 by a toggle mechanism, but they will be moved quickly bysprings 8 into the dotted line position, Fig. 3, when the togglemechanism is tripped. The toggle mechanism will be, hereinafterdescribed- The block 0 has upstanding side walls 19, longitudinalpartitions 20 and a transverse partition 21. These walls and partitionsconstitute arc-shields. The partition 21 forms a shield between thecontacts 12, 13 and 14 and the adjacent contacts 6, 8, and 10 and thelongitudinal walls and partitions constitute shields between these pairsof contacts 67, 8-9, 10-11', and between the several contacts 12, 13,and 14.

Three similar metal strips 22 are secured to a block of insulatingmaterial 23 on the base and these metal strips have downwardly turnedends which carry binding posts 24, 25, and 26 to which the terminals ofthe supply circuit are connected. As illustrated in Fig. 3, the support22 has an overturned end 9 m full lines, the springs 30 hold the contactstrips yieldingly against the contacts 12, 13,

and 14. As shown in Fig. 3, contacts 8 and 13 are connected together bya connector 13*, at the rear side of the'block c. Similarly the contacts12 and 6 are connected by a connec tor 12 and the contacts 14 and 10 areconnected by a connector 14 Thus, through the parts just describedthecontacts6, 8 and '10 M are normallylccnnected;t the supply wire P 20terminals, and when the magnet is energized theicontactor 3, '4, andwill connect the convtactsfi, 8,..and with the contacts 7, 9, and 11,respectively; Y

-- :The contact"? is electrically connectedto -the hinged side bar'15 bya metal strip 31,

"anducontact'lli is connected to'the side bar 116 by a metal strip 32.The side bars thus tacts 7 and 11 with the inetal posts 17 and 18.

" 0 The contact 9 isconnected by a Wire 33 to 'a binding post 34. Theleads35, 3 6, and 37 to 'a multiphase motor mare lshown connected to thepost 34 and the posts-17 and 18, respectively. The coil of the magnet bis in a cir- 35 ;cuit which extends from the contact6 through conductor38 to a manually operated switch f 39, thence by conductor40to the coiland by conductor '41 to the contact 8. Ordinary stop and start pushbuttons will be employed '4 for controlling the 'magnct and" when themain switch closesit will establish a holding circuit for the magnet,.inaccordance with (the common practice, but -for' the sake of The sidebars 15 and 16. are shown in the tornrof'chann'els and'within thechannels, at

the free ends of the bars, are arranged links -42, ofinsulatingmaterial, which are pivoted 1'50 to'the bars andalso to theend portions of a -rod 43 which extends through arms 44 of'a .bail 44. Arod 45 extends through'the'ends of the bail 44 and also through the arms46 -of a bail;46 which'is secured to the bases,

.5 1 with its'armsprjojecting upwardly therefrom. V

[A sleeve 47 is jourrialed on oneend of .the' rod .-.45,and carries ahandle -48 which'prej ects at rightangles to the sleeve. Asegmen't 49v isecured to the sleeve. andthe rod'43 projects ,60 throughasegmental slot50 in the segment as -s hown;i n Fig--24 The links 42andthe arms f,44Pform a toggle, the members ofwhich normallystand in the positionshown in Fig. 2. Ihe,springsfsfconstantly tend to pullthe side tfifrails v and the JblQQk 0 toward the base. If

the operator moves the handle 48 downwardly, in Fig. 2, a certaindistance, the toggle breaks and the springs s then quickly draw the siderails of the block from the full line position in-Fig. 3 tothedottedline position,

thus moving the contacts on the block away from the .contactor. arms3,14, and 5 and from the contact strips2'Z, 28, and 29. By moving magnetis energized its armature moves the switch-arms orcontacto'rs 3, 4, and5 into enga'gement with'the pairs of main switch contacts 6"'7, 8'9, and10- 11, and the motor- "circuits are thus completed from the supplywires 51, 52, and 53 tothe motor. When the operatorwishes to stop the'motor,fhe inter rupts the circuit to the magnet'and the arms 3, 4, and5 fallinto open position by gravity, each arm makinga double break intheleg of p the motor circuit=which it: controls.

,serveas conductors. for connecting. the con- .3

. If, for any reason, such asgrounding of the magnet coil,'the mainswitch fails to open wardly into position to unlock the toggle leverwhen the insulating block 0 will be quick ly drawn to the dotted lineposition, thus moving the main switchcontacts on the block away from thearms 3, 4, and 5 and the line contacts 12, 13, and 14 away from thespring pressed connectors 27,28, and 29. Each leg of the motorcircuits'will thus be broken so; 1

that very little; arcing will result. At the same time the circuit forthe'magnet will be broken at the-contacts 6 and 91 I wsimplic'ity. Ihave shown a simple on and r 45 ofl"switc'h 39 for the magnet circuit. 3

- Blow-out magnets may be mounted on the contact-carrying block; InFigs. 6 to 8 of the jdrawin'gs, Ihave shown, for. illustration, a

. ried by pivoted brass arms 15 and 16 and a spring-pressed contactmember 57, extending from a line terminal. 58, bears upon av linecontact 59 on'the block. The base of the block is arched'forwardlybetween contacts 56 and 59, as shown at 60, to accommodate the c0il'61of a blow-outmagnet the core 62 of 'whichextends transversely of theblockand jisjconnected at'its 'endsto sheet metal pole pieces 63 whichliein recesses 64 in, the outer sides of the-longitudinal arcshields.

Each polepiece is of the form shown in Fig.

9, having downwardly converging side edges 1 v and thence to supply wire7 2.

'63" and anxopening 63 near itslower end,

and the recesses 64 which receive the pole pieces have their side wallsconverging downwardly as shown at 64", so that when the pole pieces areplaced in the recesses they will be supported by the converging walls ofthe latter. The magnet core has pintles 62 at 1ts ends which extend intothe opening 63 in bracket 66,.which is secured to the base, a

sleeve 47 secured to the shaftand a hand lever 48 projecting from thesleeve, which carries a slotted segment 49, the same as the segment inthe previously described figures. Links 67 connect the shaft 65 with ashaft 68, one end of which extends through the slot in the segment. Alink 69, of insulating ma terial, is pivotally connected to the shaft 68and to the central part of a rivet pin 7 O which extends through theside bars 15 and 16 and the block 0 A supply wire 71 is shown connectedto the binding post 58 and the other supply wire 7 2 is shown connectedbyconductor 73 to one terminal of a motor m and the other terminal ofthe motor is connected by wire 74 to a binding post 75. A flexibleconductor 76 connects this binding post with the switch arm 55. Themagnet circuit extends from the switch contact 56 through conductor 77to the magnet coil, and thence through manually controlled switch 65 tothe conductor 73,

In operation, the contact-carrying block is normally held in theposition shown in Fig. 7 and the supply wire 71 is normally connected tothe contact 59 through springpressed connector 57. VVhen'the switch 65is closed, the magnet attracts the armature 1 and the switch arm isdrawn into engagement with the contact 56. Current then flows to themotor from supply wire 71 through binding post 58 and connector 57 tocontact 59, thence through the coil 61 of the blow-out magnet to contact56, thence through switch arm 55, flexible conductor 7 6 and conductor74 through the motor and thence through conductor 73 to the supplywire 72. 1 When the switch is opened, the magnet becomes deenergized and thearmature rocks by gravity away from the pole piece, carrying the switcharm 55 out of engagement with the contact 56, thereby opening the motorcircuit and stopping the motor. The are between the arm 55 and'contact56' is extinguished by the blow-out magnet. If this main switch .failsto open by reason of grounding of the magnet coil, or for any otherreason, the operator can break the circuit through the motor by swingingthe hand lever 48 downwardly, thereby breaking the toggle, and thesprings s will then swing the side bars and contact-carrying blocktoward the base, thus moving the main switch contact 56 away from theswitch arm and the line contact 59 away from the connector 57 so thatthe motor circuit will be broken in two places, and the blow-out magnetwill extinguish the arcs at both places. Also, the circuit through themagnet will be broken at these two places.

WVhat I claim is:

1. A motor control switch mechanism comprising a normally stationarycontact, a switch member having a limited range of movement toward andfrom said contact and for quickly moving the contact beyond the range ofmovement of said member.

2. A motor control switch mechanism comprising a block of insulatingmaterial, a switch contact on said block, a switch member having alimited range of movement toward and from said contact and biased awayfrom the contact, a magnet for moving said member into engagement withthe contact, and manually controlled means for quickly moving the blockto carry the contact beyond the range of movement of said member.

3. A motor control switch mechanism comprising a switch member having alimited range of movement, a block of insulating material, a switchcontact on said block and normally within said range of movement, amagnet for moving said member into engagement with said switch contact,a line contact on the block, a stationary line terminal, a contactmember extending from said terminal and normally engaging said linecontact, and manually operable means for moving said block to carry saidswitch and line contacts out of engagement with said switch member andsaid contact member, respectively.

tact,said magnet having its coil connected to said line contact, andmanually operable means for moving said block to carry said switch andline contacts out of engagement with sandy switch member and saidcontact member, respectively.

5. A motor control switch mechanism com- A prising a block of insulatingmaterial, a pair of switch contacts and a line contact on said block,one of said switch contacts being con nected'to said "line contact,a'switch member having alimited range of movement and adapted to engageand bridge said switch con tacts, a magnet for moving said switchmemherinto engagement with the latter contacts, a stationary line terminal, acontact member extending from said terminal and normally engaging saidline contact, and manually operable means for moving said block to carrysaid switch and line contacts out of engagement with said switch memberand said contact member, respectively.

6. A motor control'switch mechanism comprising a block of insulatingmaterial, a pair of switch contacts and a line contact on said block,one'of said switch contacts being connected to said line contact, aswitch member having a limited range of movementand adapted to engageand bridge said switch contacts, a magnet for moving said members intoengagement with the latter contacts, a

stationary line terminal, a contact member 7 extending from saidterminal and normally engaging said line contact, said magnet having itscoil electrically connected to said line contact,-and manually operablemeans formoving said block to carry said switch and 'line contacts outof engagement with said switch member and said contact member, re-

spective'ly. r

7. A motor control switch mechan sm comprising a switch member havingalimited range of movement, a movable block of insulating material, aswitch contact on the block, a magnet for moving said member into 7engagement with said contact, a toggle mechv anism adapted to hold theblock and contact block and contact awayfrom said when the toggle istripped.

in position so'that said member may engage the contact, and a springadapted to move the position tact on the block, a stationary lineterminal,

a magnet for moving said member into engagement with said switchcontact, a line contact-on the block, a stationary line terminal, acontact member extending from said terminal and normally engaging saidline contact, a blow-'outmagnet carried by the, block and having itscoil termlnals connected to said contacts, and its'pole pieces adjacentboth ofsaid contacts, and manually operable means for moving saidiblockto carry said switch andjline contacts out of engagement with saidswitch member and said contact member, respectively. 7 V

In testimony whereof'I affix my signature.

GEORGE H. 'WHITTINGHAM.

8. A motor control mechanism com risin a switch member having a limitedrangeof 'movement, a pairiof levers, ablock ofinsui I lating materialmounted' 'onsaid levers,'a sw tchcontact on the block, a magnet formoving saidmember into engagement with "said contact, a manuallyoperable toggle'normally'supporting the levers and block with thecontact in position to be engaged by said member, anda spring adaptedtomove the I levers and block to carry the contact out of the range ofmovement of saidmember, when fthe toggle is tripped. W Y v, V p v ,9. Amotor control switch mechanism com- 1 prising a switchmember havingalimited range of movement,a block-of insulating material, a switchcontact on said block and normally within said range of movement, amagnet for moving said me'mber 1nto ,en-

gagement with said switch contact, a line 0011-

